单项选择题
【案例分析题】
Pigs have always had a bad press.Such expressions as ’piggish’，’pig-headed’，’buy pig-in-a-poke’，’hog-wash’，’hog-wild’and ’hog-heaven’suggest how low is their esteem.Several religions proscribe（排斥）the animal entirely.
Pigs have been around for 35million years and the pig’s brain is thought to be inferior only to those of primates （灵长目动物）and dolphins.Because people and pigs have similar digestive，cardiovascular（心血管的）and respiratory systems，they suffer from many of the same illnesses.Pigs are extensively used in medical laboratory experiments for the benefit of humans and they also supply some body substances and parts for humans.
Pigs have served mankind mainly as food.Pigs can live from 12to 15years but are slaughtered at seven months.The selective breeding of pigs caused them to lose their natural immunities（免疫力）and they must be given shots to ward off diseases.
Pigs are relatively clean when given the opportunity，can be house-broken，are affectionate，and communicative.Some people have adopted a pig as a pet and a few pigs have become famous.Perhaps the pig is gaining a new respect—thanks to movie and TV antics of Porky Pig and Miss Piggy.’Pigs are beautiful’is the motto of porcine（像猪的）pet owners and members in 22states and five nations，and each is the booster（支持者）of pet pigs.
The author of this article maintains（）.
